1. Field of the Invention
This invention relates to computer systems and, more particularly, to backup file restoration within computer systems.
2. Description of the Related Art
It is common practice for individuals and enterprises to protect data that resides on a variety of computer hosts via some type of backup mechanism. For example, numerous client devices may be coupled to a network to which a backup server is also coupled. The backup server may be further coupled to one or more tape drives or other backup media. A backup agent on each host may convey data files to the backup server for storage on backup media according to a variety of schedules, policies, etc. To facilitate restoring backup files, the backup server may maintain a catalog of the files that have been stored on the backup media. When a client wishes to restore a file, the server may present a view of the catalog or a portion of the catalog from which the client may make a selection. Once the client has indicated which file is to be restored, the backup server may initiate a restoration process.
In large systems, each client may include a backup agent and responsibility for backup and restore operations may be distributed among one or more backup servers and the backup agents. Instead of or in addition to the backup catalogs kept by the backup servers, each agent may include a local backup catalog of its own, storing data specific to its associated client. During a restore operation, a backup agent may first query the local backup catalog, thereby avoiding the delay that may be associated with querying the backup server's catalog.
Unfortunately, even when local backup catalogs are used, the restoration process may be slow and inefficient. For example, because many clients typically share a small number of backup servers, the restoration process may be slowed by network latencies. Restoration may be further slowed if a slow or busy WAN link connects the backup server to its clients. Also, for tape-based backup, once a file has been identified for restoration, administrator assistance may be required to mount the particular tape that contains the desired file, increasing expense and turnaround time. In addition, files that have not been backed up are not available for restoration. In view of the above, an effective system and method for restoration of files that accounts for these issues is desired.